Bin discharge apparatus



NOV. 21, s SAYRE BIN DISCHARGE APPARATUS 2 Sheets-Sheet 1 Filed April 2, 1959 INVENTOR. HOWARD S. SAYRE 6; M

Nov. 21, 1961 H. s. SAYRE 3,009,607

BIN DISCHARGE APPARATUS Filed April 2, 1959 2 Sheets-Sheet 2 FIG. 4-

' INVENTOR. HOWARD S. SAYRE United States Patent 3,009,607 BIN DISCHARGE APPARATUS Howard S. Sayre, Bethlehem, Pa., assignor to Fuller Company, a corporation of Delaware Filed Apr. 2, 1959, Ser. No. 803,614 12 Claims. (Cl. 222-195) The present invention relates to a self-unloading bin or receptacle for pulverulent material of the type having a gas-permeable deck in the bottom thereof through which a gas is caused to flow into the overlying material in such volume and at such pressure as to fluidize the material and to cause it to flow along the upper surface of the deck towards a discharge outlet.

Heretofore, the use of flexible, gas-permeable fiuidizing decks such as tightly-woven canvas in large bins or receptacles has required an arrangement of relatively narrow courses of gas-permeable deck or fluidizing areas which are separated by steep slope sheets, or an assemblage of a plurality of such courses positioned adjacent each other to form a composite fiuidizing area. The steep slopes required in such sheets to insure discharge or passage of the material downwardly therealong to the fluidizing sections cause the slope sheet assemblies to consume a considerable portion of the interior volume of the bin, thereby reducing the effective storage capacity of the bin or receptacles and raising the center of gravity thereof, which is particularly undesirable in vehicle-mounted bins.

The physical nature of flexible, gas-permeable decks is such that a substantially-uniform support is required to provide adequate distribution of the heavy loads often encountered in large bins. This is particularly true in the case of large vehicles, such as highway trailers or railroad cars, in which the deck is not only required to support the substantial head or weight of material, but also is subjected to the additional stresses of vertical shocks during motion of the vehicle. If disproportionate amounts of stress are located in a particular area of the gas-permeable deck, such as by uneven tensioning of the material in the deck, failure is likely to result. Therefore, when substantially complete aeration of large areas is required, it has been necessary to employ a side-by-side arrangement of individual, relatively-narrow, gas-permeable decks supported by and secured to individual plenum chambers which are, in turn, individually supported on the frame of the bin-support or vehicle, as the case may be. This construction results in high costs of manufacture and assembly, and is particularly troublesome in terms of the time and labor required to secure the edges of each of the decks to the respective plenum chambers. Typically, these edges are secured by a plurality of bolts spaced longitudinally of the edges about four inches apart which pass through the deck and outwardly-extending flanges of the plenum chamber, and are secured thereto by nuts or by threading into the flanges of the plenum chamber.

Heretofore, no satisfactory arrangements have been known by which a relatively-large, or full-width sheet of flexible, gas-permeable deck material could be installed in large bins, particularly because of the difiiculties in producing a uniform load-supporting ability throughout the deck.

The present invention contemplates large bins or receptacles for the storage or discharge of pulverulent material having flexible gas-permeable decks which extend over substantially the entire floor area of the bin and which are so supported that adequate distribution of heavy loads are provided without any substantial sagging or distortion of the gas-permeable media forming the decks.

In general, the preferred form of apparatus ,of the present invention, as embodied in a center-discharge bin, comprises a bin or receptacle having side walls, end walls,

a top wall, and a pair of bottom walls sloping down- Wardly towards the center of the bin or receptacle. The lower ends of the bottom walls are spaced from one another to provide for the discharge of material. A pair of cross walls extend between the side Walls, downwardly from the lower edges of the bottom walls, and an underlying floor having a pair of discharge outlets therein closes the space between the lower edges of the bottom walls.

The major portion of each of the bottom. walls is formed as a transversely-discontinuous plane having a plurality of upstanding, relatively-narrow, longitudinallyextending ridges of inverted U-shape in cross section. The ridges are separated by a plurality of depressed areas forming the bottom of plenum chambers Which are closed at their respective ends by the adjacent end walls of the bin or receptacle and the cross walls. Means are provided for introducing air or gas, under pressure, individually to the several plenum chambers. Channel-edge members, of inverted U-shape in cross section, are positioned between the longitudinal edges of the main portion of the bottom walls and the side walls of the receptacle and complete the bottom walls or floor structure of the bin. The upper surface of the base of these edge members has portions lying in the plane of the top of the longitudinally-extending ridges.

A flexible, one-piece, gas-permeable deck extends over the full length and substantially the full Width of each of the bottom walls. It rests upon and is secured to the bases of the inverted U-shaped ridges and forms the upper wall of the several plenum chambers formed between the respective ridges of the bottom walls.

The side edges of the gas-permeable decks are secured, under lateral tension, to the upper surfaces of the channel side-edge members by edge-clamping means, while intermediate longitudinal sections thereof are secured to'the upstanding ridges over which they are stretched. The edge-clamping means include portions which extend upwardly and outwardly from adjacent the inner longitudinal edges of the channel-edge members to the adjacent side walls of the receptacle. These portions also function as sloping sheets at the sides of the bin and as a cover for the edges of the gas-permeable deck. The stretching of the flexible media forming the gas-permeable decks and the securing of them to both the side edge members and the longitudinally-extending ridges assures that they will have a uniform load-supporting ability throughout and will not sag or become distorted under heavy loads.

The invention will be further described in connection with the accompanying drawings in which:

FIG. 1 is a longitudinal sectional view of a bin or receptacle embodying the invention, the same being taken along line 11 of FIG. 2;

FIG. 2 is a horizontal sectional view taken along the line 22 of FIG. 1;

:FIG. 3 is a cross-sectional view, on an enlarged scale, taken along the line 33 of FIG. 1; and Y FIG. 4 is a transverse sectional view, similar to FIG. 3, on a further enlarged scale, of the manner of securing the gas-permeable decks to the longitudinally-extending ridges and the channel side-edge members. 7

In the drawings there is shown a bin or receptacle which may be either stationary or which may form a part of a trailer, railroad car, or other mobile vehicle. The bin comprises a casing 1 having a pair of side walls 2 and 3, a pair of end walls 4 and 4, and a pair of bottom walls 8 and 8'. The bin is closed by top wall '6 having a pair of material inlets 7 and 7'. The bottom walls 8 and 8' slope downwardly adjacent the respective end walls 4 and 4 toward the center of the bin. The bottom walls terminate short of the longitudinal center of the bin, and a pair of cross walls 9 and 9' extend transversely of the bin and downwardly from the .inner ends of the respective bottom walls. A floor section 11 joins the lower edges of the cross walls, and with such cross walls form a trough extending transversely of the receptacle between the lower ends of the bottom walls. The trough it) has a pair of material-discharge outlets 12 and 13 extending downwardly from the floor 11 thereof. The lower ends of the discharge outlets are provided with flanges 14 and 15, respectively, to which the intake end of a conveying line may be attached, if desired. Preferably, the floor 11 is constructed so as to be readily detachable from the cross walls 9 and 9' and the side walls of the bin to facilitate the assembly of the respective parts of the bin, as hereinafter described. The floor 11 may be detachably secured to the cross walls 9 and 9' and the side walls of the bin in any suitable manner, such as by bolts passing through flanges on the edges of the floor and extending from the lower edge of the cross walls and the side walls of the bin.

The main portion of the bottom walls 8 and 8 are formed as a transversely-discontinuous plane to provide a plurality of spaced, raised, longitudinally-extending ridges 17 and 17', respectively, preferably odd in number. These ridges are substantially-evenly spaced between the side walls 2 and 3 and are separated from each other by bottom floor portions 21, 21 located in planes below the ridges and connecting adjacent edges of the ridges.

The ridges 17 and 17' each comprises an inverted Ushaped section having a substantially-fiat base 24 which is joined to the respective floor portions 21, 21 by side walls 25 and 26. The corners 25a and 26a, at the junction of the base 24 and the side walls 25 and 26, respectively, are rounded along a radius of curvature of between one-fourth and three-fourths of an inch.

The longitudinal side edges of the main portion of the bottom walls are welded or otherwise secured to the inner edges of side edge members 18, 18 and 19, 19, which extend along the side walls 2 and 3 of the bin and form the remainder of the bottom walls thereof. The ridge members are channel irons of inverted U-shape in cross section. The upper side of the base of each of the side edge members has a longitudinally-extending raised portion 43 extending the full length thereof. The inner edge 44 of the raised portion 43 is flush with the outer side of the inner flange 42 of the edge member. Each raised portion extends inwardly along the upper surface of its associated edge member about one-third the width of such upper surface, where the raised portion terminates in an outer edge 44. The upper surfaces of the raised portions of the edge members lie in the same plane as the upper surfaces of the ridges 17 and 17.

Flexible gas-permeable decks 16 and 16, preferably formed of multi-ply woven textile material of the general character of that used for canvas belting and having a relatively low, uniform gas-permeability, are stretched across the bottom walls 8 and S and have their longitudinal edges extending over the raised portion 43 and secured to the upper surface of the side edge members by longitudinally-extending clamping members 45 extending the full length of the side edges of the gaspermeable deck.

The gas-permeable decks 16 and 16 slope downwardly from the respective end walls 4 and 4 to adjacent the cross walls 9 and 9. permeable decks preferably is at least equal to the angle of repose of the pulverulent material, when aerated, which is to be stored in and discharged from the bin, and may be, for example, in the range of from 5 to 15.

Each of the clamping members 4'5 is positioned above the side edge members and comprises a clamping frame 47 above and in vertical alignment with the raised portion 43 and a combined covering wall and slope sheet 58. The covering wall slopes upwardly and outwardly from the inner side of the frame 47 to the adjacent side wall of the bin. The inner edge portion of the covering wall is turned downwardly to form a vertical wall 49 having its lower edge bearing against the upper surface of the The angle of slope of the gas-.

gas-permeable deck slightly inwardly from the vertical plane of the inner side of the flange 42 and the aligned inner edge 44 of the raised portion 43. The downwardly turned inner edge of the covering wall is welded or otherwise secured to the inner edge of the frame 47. The outer edge portion of the frame 47 is also turned down to form a vertical edge wall 50. The wall 50 is in a vertical plane slightly outwardly from the outer edge 44 of the raised portion 43. The downwardly turned edge portions 49 and 5t) and the Web portion of the frame 47 form an inverted U-shaped channel having an inner horizontal dimension of slightly greater width than the width of the raised portion 43.

A plurality of longitudinally spaced bolts 51 are welded or otherwise secured to the underside of the web of the frame 47, and after the gas-permeable deck is strethccd laterally across the upper surfaces of the ridges 17 and the inner portions of the side edge members, are passed through correspondingly spaced and aligned openings in the adjacent edge portion of the gas-permeable deck and the web or base of the side edge members. Nuts 52, with interposed lock washers 53, are then screwed onto the bolts until the frame 47 tightly clamps the edge portion of the gas-permeable deck against the side edge members. During this clamping operation, the lower edge of the vertical wall 49 engages the gas-pcrmeable deck just inwardly of the inner face of the flange 42 and exerts a force thereon and and bends it slightly around the corner at the inner edge 44 of the raised portion 43, further stretching the gas-permeable deck across the upper sur face of the ridges 17. in a similar manner, the lower edge of the wall 53 engages the outer edge of the gaspermeable deck outwardly beyond the outer edge 44 of the raised portion 43 and bends the gas-permeable deck around that edge and forces it down against the upper surface 40 of the side edge member. In this manner. the side edges of the gas-permeable decks are securely clamped to the side edge members, and the gas-permeable deck is held taut in its stretched condition and prevented from sagging into the spaces between the longitudinallycxtending ridges 17 and 17 under the pressure or head of the overlying pulverulent. material.

A plurality of longitudinally extending clamping members 27 and 27 are arranged individually above the ridges 17 and 17, respectively, and clamp the gas-permeable decks to the ridges where they pass over them. The clamping members 27 and 27 each comprises a hollow housing or cover section 28 having an upper section 29 of inverted V-shape in cross section and a pair of lower vertical side walls 31 and 32. The lower edge portions 31a and 32a, respectively, of the side walls 31 and 32, are curved and turned inwardly towards the center of the cover section along a radius of curvature slightly in excess of the radius of the corresponding corners 25a and 25a of the ridges 17. The upper ends of the cover section 28 are closed by the end walls 4 and 4- of the bin while the lower ends are closed by suitable end walls 38.

A clamping frame or plate 33, which may be either a single longitudinal unit or a plurality of spaced members, rests upon the inner, upturned edges 31a and 32a. A plurality of longitudinally spaced bolts 34 are welded or otherwise secured to the underside of the frame 33 and are positioned to pass through aligned openings in the gas-permeable deck and aligned openings 35 in the upper base 24- of the ridges 17 and 17'.

When the clamping members 27 and 27' are placed over the ridges 17 and 17, with the bolts 34 passing through the aligned openings in the gas-permeable decks and the nuts 36 with interposed lock washers 37 screwed tightly onto the bolts, the frames or plates 33 engage the inner edges of the inturned lower edge portions 33a and 32a and force their lower curved portions against the upper surface of the gas-permeable deck and clamp the gas-permeable deck against the upper base portion 24 of the ridges 17 and 17.

The distance between the crests of the curved surfaces of the portions 311: and 32a which engage the upper surface of the gas-permeable decks is slightly greater than the width of the base portions 24 of the ridges. Therefore, when the portions 310 and 32a are forced against the upper surface of the gas-permeable decks, they will engage them outwardly beyond the side walls 25 and 26 of the ridges 17 and 17 and exert a downward forceagainst the gas-permeable decks tending to force them around the corners between the bases 24 and the side walls 25 and 26 of the ridges. This insures that the gaspermeable decks will be effectively held in tightly clamped position against the ridges l7 and 17, in a manner similar to that in which the edges of the gas-permeable decks are held in clamped position to the side edge members 18, 18 and l9, 19. Thus the clamping members 27 and 27' cooperate with the side clamping members 45 to hold the gas-permeable decks tightly stretched across the bottom walls of the bins and supported against sagging or distortion under the pressure or load exerted by the overlying material.

The gas-permeable decks 16 and 16' cooperate with the main sections of the bottom walls 3 and 8 to form a plurality of longitudinally-extending plenum chambers 22 and 22 between the ridges 17 and 17 and underlying the gas-permeable decks. The upper or outer ends of the plenum chambers are closed by the end walls 4 and 4- of the bin, while the lower or inner ends are closed by the cross Walls 9 and 9.

A plurality of individual inlet pipes 23 and 23 supply air or other gas under pressure from a source, not shown, to the plenum chambers 22 and 22 to pass upwardly through the gas-permeable decks into the overlying material to fluidize it and to cause it to how downwardly along the upper surfaces of the gas-permeable decks to the trough ll) from which it is discharged. The inlet pipes 23 and 23' are provided with individual valves 23a and 23a, respectively, so that the amount of air or other gas supplied to the several plenum chambers may be controlled.

A plurality of transverse bars 55 bridge the space between the ridges 17 and 17 at the upper and lower ends of the plenum chambers and provide flat upper surfaces or ledges 56 for supporting the ends of the gas-permeable decks between the ridges. The ends of the gas-permeable decks are secured to these bars by suitable fasteners, such as blind rivets. The surfaces or ledges 56 preferably are at a level slightly below the level of the upper surfaces 24 of the ridges. The difference in level between the upper surfaces or ledges 56 and the upper surfaces of the ridges preferably is one-eighth of an inch or less. With the upper surfaces or ledges 56 at a slightly lower level than the upper surfaces 24 of the ridges, the securing of the ends of the gas-permeable decks to the ledges will cause them to bend downwardly around the corners of the upper surface of theridges and better secure them in place and more permanently hold them against distortion.

A plurality of fluidizing conveying sections comprising gas-permeable decks 57, 58, 59 and 60, respectively, are mounted on the floor 11 of the trough 10 formed between the side walls 9 and 9. The gas-permeable decks 57 and 58 slope towards the outlet 12 from adjacent the side wall 2 and form the longitudinal center of the bin, respectively, while the decks and 6t) slope downwardly toward the outlet 13 from adjacent the longitudinal center of the bin and form the side walls, respectively.

'A" plurality ,of supporting walls dl, extending transversely of the trough 1d, extend upwardly from the floor 11 and support the edges of the gas-permeable decks 5'7, 58, 59 and 6d, and form a plenum chamber 62 beneath deck 57, a common plenum, chamber 63 beneath the center decks- 5S and 59, and a plenum chamber 64 beneath the deck 6%. A plurality of inlet pipes 65, 66 and 67 supply air or other gas, under pressure, from a source,

not shown, to the plenum chambers 62, 63 and 64, respectively, to pass upwardly through the overlying gas-permeable decks into the overlying pulverulent material to fluidize it and to cause it to flow downwardly along the upper surface of the gas-permeable decks 57, 58, 59 and 69 to the discharge outlets 12 and 13. The inlet pipes 65, 66 and 67 are provided with individual valves 65a, 66a and 67a, respectively, to enable control of the amount of air or other gas supplied to each of the plenum chambers.

The construction of the bin as previously described not only has advantages in its use due to its structure, but the manner in which it is constructed also materially facilitates its assembly. 7

In assembling the complete bin, the upper portion of the casing, including the bottom walls 8 and 8' and cross walls 9 and 9', but omitting the floor 11, is formed by any known procedure. With'the bottom walls 8 and 8 secured, a continuous sheet of fabric, pre-cut to proper dimensions and comprising the gas-permeable deck 16, is passed endwise upwardly through the opening between the cross walls 9 and 9 and is spread over the bottom wall 8. The upper end of the deck adjacent the end wall 4 is then secured under suitable uniform tension over the ridges 17 to the ledges 56 by blind rivets or the like which are passed through the gas-permeable deck and the ledges. When the full width of the deck 16 has been secured adjacent the end wall 4, the opposite end adjacent the cross wall 9 is put under substantiallyuniform, longitudinal andtransverse tension and is secured to the ledges 56 adjacent the cross wall in the same manner in which the upper edges were secured to the ledges 56 adjacent the end wall 4.

The edge-clamping members 45 are then installed and the bolts 51 passed through the aligned holes in the edge portions of the gas-permeable deck and the base of the side edge members 18 and 18'. The nuts 52 and washers 53 are then run onto the bolts 51 and the nuts turned down thereon from beneath the bin. The edges 49 and 50 of the edge-clamping members 45, when pulled down by the nuts and bolts, pull the fabric of a gaspermeable deck down over and against the edges 44 and 44' of the raised portion 43 of the side edge members. Since the edges 49 and 50 of the edge-clamping member 45 are spaced apart a distance slightly greater than the edges 44 and 44', the fabric is partially forced down around the edges 44 and 44' and securely clamped to the side edge members and held under uniform tension over the main portions of the bottom wall 8. The bend or deflection of the fabric around the several edges is formed on a radius of substantial magnitude which may be, for example, of the order of five or six inches, to prevent cutting and fatigue of the fabric such as would take place if the fabric were bent over sharp corners of short radius When the edges of the gas-permeable deck have been secured, the odd numbered clamping member 27 in the center. of the gas-permeable deck is installed in the manner heretofore described. Securing of the longitudinal center of the gas-permeable deck to the center ridge 17 divides the tension evenly between the edges adjacent the side Walls 2 and 3 and prevents excessive tensioning adjacent one edge or the other. After the center clamping member has beenfastened in place, the remainderof the clamping members 27 are theninstalled, thereby causing the gas-permeable deck to be "divided into a series of consecutive divisions of free fabric areas of evenly ten sioned halves.

The greater spacing of theedges 31a and 32a of the clamping members in relation to the spacing ofthe edges 25a and 26a of the ridges causes the'ifree fabric areas to be partially forced down aroundthe edges -25 and 26 and t0 befurther tensioned transversely over those curved edges in smooth transitional curves of. substantial radius, which may be, for example, of the order of six inches radii.

After the deck 16 has been installed and secured in place as described above, the same procedure is used in installing the gas-permeable deck 16 at the other end of the bin, after which the pre-assembly of the floor 11, on which are mounted the gas-permeable decks 57, 58, 59 and 60, plenum chambers 62, 63 and 64, inlet pipes 65, 66 and 67, and the discharge members 14 and 15, is fitted into place to complete the assembly.

In operation, the pin is filled with fluidizable, pulverulent or granular material through the inlets 7 and 7. When it is desired to discharge a portion or all of the contents, the bin is vented, as by opening one of the inlets, or in any other manner, and air or other gas, under pressure, is introduced to the plenum chambers 62, 63 and 64, through the inlet pipes 65, 66 and 67, while a similar supply of air or other gas is delivered to a selected pair or group of plenum chambers 22 or 22 through the appropriate inlets 23 or 23'.

The introduction of the air or other gas to the plenum chambers may be controlled by any known means, such as the valves included in the gas supply pipes, and in any grouping or sequence desired. A preferred sequence of operation includes continuously introducing the gas through the decks 57, 58, 59 and 60, during the unloading, and introducing air to the inner pair of plenum chambers 22 at one end of the bin and the inner pair of plenum chambers 22' at the other end of the bin which are aligned with the central gas-permeable decks 58 and in the trough 10, adjacent the outlets 12 and 13.

Air introduced into the selected chambers 22 and 22' passes upwardly through the associated areas of the gaspermeable decks 16 and 16' into the overlying material, fluidizing it and causing it to flow by gravity downwardly along the gas-permeable decks 16 and 16 and onto the gas-permeable decks 58 and 59. The gas passing upwardly through the gas-permeable decks 58 and 59 maintains fiuidization of the material delivered to them from the gas-permeable decks 16 and 16, which material then flows along the decks 58 and 59 to the outlets 1.2 and 13, from which it may pass into a conveying line to be delivered to some remote place or into some other vehicle for transport. As material fiows from the inner Zone of the bin, a portion of the material of the other plenum chambers, which is not fluidized, will fall or slide over into the inner zone of the central plenum chambers 22 and 22' and be fluidized therein for discharge, as previously described. When the greater part of the material from the areas over the inner pairs of plenum chambers has been removed, the rate of discharge from those areas will consequently be reduced. The plenum chambers underlying the previously selected inner areas of the gas-permeable decks may then be cut off from the gas supply and the outer pairs of plenum chambers 22 and 22 adjacent the side walls supplied with the fluidizing gas until the greater part of the bin contents has been dischanged, and the discharge rate again falls 0E. The full gas supply is then delivered to all of the plenum chambers 22 at one end of the bin, until unloading from that end of the bin is complete, after which the full gas supply is charged over to all of the plenum chambers 22 at the opposite end of the bin to cause complete clean-out of the bin.

The provision of a plurality of plenum chambers in each end of the bin permits localized introduction of gas to facilitate initial pre-fiuidization of a difficultly-fluidizable material, such as cement or sugar, which is sensitive to moisture conditions, or correction of a local Zone where fiuidization of the material within the material mass is found to be difiicult.

When: thebin of the present invention is mounted on or forms partof a vehicle, trips of great distance may result in a high degree of compaction of the material within the bin. In such cases, the full gas supply may be delivered to a selected one or more of the plenum chambers to effect a break-through and pre-luidization to loosen the material in preparation for unloading.

Various changes may be made in the details of construction of the bin as described without departing from the scope of the invention or sacrificing any of the advantages thereof.

I claim:

1. A self-unloading bin for pulverulent material comprising side and bottom walls, an inclined gas-permeable deck extending downwardly from each of two opposite side walls towards a transverse section of the bin, the lower ends of the gas-permeable decks being spaced from one another, a trough between the lower ends of said gas-permeable decks to receive material discharged from the lower end of the gas-permeable decks, at least one discharge outlet leading from said trough, each of said gaspermeable decks extending across the major portion of the bin transversely of the direction of incline of said gaspermeable decks and above the bottom wall, means for securing the side edges of each gas-permeable deck adjacent the side walls of the bin, the bottom wall beneath each gas-permeable deck comprising a major central portion having a plurality of spaced ridges extending longitudinally thereof in the direction of incline of the respective gas-permeable decks, and side edge members bridging the space between the edges of said major central portion and the side walls of the bin, the side edge members having upper surface portions in substantially the same plane as the upper surfaces of said ridges, the edge portions of the gas-permeable decks extending over said upper surface portions of said edge members, means for stretching the gas-permeable deck across said ridges and securing the edge portions thereof to the edge portions of the gas-permeable deck to said side edge members, means for securing said gas-permeable decks to the upper surface of said ridges, plenum chambers between said ridges, the gas-permeable decks forming the upper wall of said plenum chambers, and means for introducing gas into each of said plenum chambers to pass upwardly through the gas-permeable decks and into overlying pulverulent material to fluidize said material to cause it to flow downwardly along the upper surface of the gaspermeable decks into said trough for discharge.

2. A self-unloading bin for pulverulent material comprising side and bottom walls, an inclined gas-permeable deck extending downwardly from each of two opposite side walls towards a transverse section of the bin, the lower ends of the gas-permeable decks being spaced from one another, a trough between the lower ends of said gaspermeable decks to receive material discharged from the lower end of the gas-permeable decks, at least one discharge outlet leading from said trough, said trough comprising cross walls at the lower ends of said gas-permeable decks and a removable bottom wall, a plenum chamber in said trough carried by said removable bottom Wall, said plenum chamber having a gas-permeable deck, said removable bottom wall also having said discharge outlet, whereby the removable bottom wall of the trough, the plenum chamber and the discharge outlet carried by the removable bottom wall may be removed as a unit.

3. A self-unloading bin for pulverulent material comprising side and bottom walls, an inclined gas-permeable deck extending across the major portion of the width of the bin in one direction and above the bottom wall, means for securing the side edge portions of the gas-permeable deck to side portions of the bin, a plurality of substantially-parallel, elongated, longitudinally-extending plenum chambers beneath the gas-permeable deck, said gas-permeable deck forming the upper wall of said plenum chamber means for introducing gas into said plenum chamber to pass upwardly through said gas-permeable deck and into overlying pulverulent material to fluidize it and to cause it to flow downwardly along the upper surface of said gas-permeable deck towards the lower end thereof, the bottom wall having at least one upstanding ridge between adjacent plenum chambers extending substantially parallel to said secured side edge portions of the gaspermeable deck and supporting said gas-permeable deck against sagging or distortion between adjacent plenum chambers, a hollow housing above said ridge and the gaspermeable deck and extending longitudinally of said ridge and having side walls, the lower edges of which are turned inwardly and upwardly, providing curved portions engaging the upper surface of said gas-permeable deck, means clamping said inwardly and upwardly turned lower edge portions against said gas-permeable deck including a frame member resting on the inner edges of said inturned lower edge portions and a fastening member secured to said frame member and passing through aligned openings in said gaspermeable deck and the ridge, and a discharge outlet adjacent said lower end of the gas-permeable deck to receive material discharged from the lower end of the gas-permeable deck.

4. A self-unloading bin for pulverulent material as set forth in claim 3 in which the distance between the crests of said inwardly-turned lower edge portions is greater than the width of said ridge, and the crests of the respective inwardly-curved lower edge portions lie outwardly of the sides of said ridge, so that when the housing is clamped tightly against the upper surface of the gas-pen meable deck, the gas-permeable deck will be forced downwardly around the upper side portions of said ridge.

5. A self-unloading bin for pulverulent material comprising side and bottom walls, an inclined gas-permeable deck extending across the major portion of the width of the bin in one direction and above the bottom wall, at least one plenum chamber formed beneath the gas-permeable deck, said gas-permeable deck forming the upper wall of said plenum chamber, means for introducing gas into said plenum chamber to pass upwardly through said gas-permeable deck and into overlying pulverulent material to fluidize it and to cause it to flow downwardly along the upper surface of said gas-permeable deck towards the lower end thereof, a discharge outlet adjacent said lower end of said gas-permeable deck to receive material dis charged from the lower end of said gas-permeable deck, the bottom wall of the bin comprising a main section having a plurality of spaced ridges of generally inverted U-shape extending upwardly therefrom and substantially parallel to the sides of the gas-permeable deck, and side edge members running lengthwise of the bin and connected at their outer sides to the side walls of the bin and at their inner sides to said main section of the bottom wall, the gas-permeable deck extending over said ridges and said side edge members, means securing intermediate portions of the gas-permeable deck to the base of said ridges, the spaces beneath said gas-permeable deck and between the side walls of adjacent ridges and between the outer side walls of the outermost ridges and the side edge members comprising plenum chambers, the upper surfaces of the ridges and at least portions of the upper surfaces of the side edge members lying in the same plane, means for securing the respective edge portions of the gas-permeable deck against the upper surfaces of said side edge members which lie in the same plane with the upper surface of the ridges, a portion of the upper surface of the side edge members outwardly from the surfaces which lie in the same plane as the upper surfaces of the ridges lying in a lower plane, the means for securing the respective edge portions of the gas-permeable deck to the side edge members including spaced means for engaging the upper surface of the gas-permeable deck outwardly and inwardly, respectively, of the outer and inner edges of the portions of said side edge members which lie in the plane of the upper surface of said ridges, and clamping means forcing said spaced means tightly against the upper surface of the gas-permeable deck and forcing the gaspermeable deck downwardly around the corners of the upper edge of said portion which lies in the plane of the upper surfaces of the ridges.

6. A self-unloading bin for pulverulent material as set forth in claim 5, in which the spaced means for engaging the edge portions of the gas-permeable deck to secure them to the side edge members are connected by a base or web member, threaded bolts are secured to the undersurface of said web or base member and pass through aligned openings in the edge portions of the gas-permeable deck and said side edge members, and nuts are threaded onto such bolts beneath the side edge members to force the spaced means into tight engagement with the upper surface of the gas-permeable deck.

7. A self-unloading bin for pulverulent material as set forth in claim 6, in which sheets slope upwardly and outwardly from the inner edges of said spaced means to the adjacent sides of the bin.

8. A self-unloading bin for pulverulent material comprising side and bottom walls, gas-permeable decks sloping downwardly from opposite side walls towards a trans verse section of the bin intermediate said opposite side walls, the lower ends of said gas-permeable decks being spaced from one another, means for securing the side edge portions of the gas-permeable deck to side portions of the bin, at least one plenum chamber formed beneath each gas-permeable deck, said gas-permeabledecks forming the upper wall of said plenum chambers, means for introducing gas into said plenum chambers to pass upwardly through said gas-permeable decks and into overlying pulverulent material to fluidize it and to cause it to flow downwardly along the upper surface of said gas-permeable decks towards the lower ends thereof, a discharge outlet adjacent the lower ends of said gas-permeable decks to receive material discharged from the lower ends of said gas-permeable decks, means intermediate the edges of said gas-permeable decks for supporting them against sagging or distortion under the pressure or head of overlying material, a trough between the lower ends of the gas-permeable decks, at least one discharge outlet extending from said trough intermediate the ends thereof, plenum chambers in said trough at opposite sides of said discharge outlet, a gas-permeable medium forming the upper walls of each of the plenum chambers in the trough, and means for introducing a gas into said last-mentioned plenum chambers to pass upwardly through the gas-permeable media forming their upper walls into overlying pulverulent material to fluidize it, the upper walls of said last-mentioned plenum chambers being inclined downwardly in a direction towards said discharge outlet, whereby pulverulent material discharged from the lower edge of said gas-permeable decks onto the gas-permeable media of the plenum chambers in said trough will be caused to flow there-along to be discharged through said discharge outlet.

9. A self-unloading bin for pulverulent material as set forth in claim 8, in which said trough comprises cross walls at the lower ends of said first-mentioned gas-permeable decks and a removable bottom wall, and the plenum chambers in the trough and the discharge outlet are carried by said removable bottom wall, whereby said bottom wall and the plenum chamber and discharge outlets carried thereby may be removed as a unit.

10. A self-unloading bin for pulverulent material as set forth in claim 8, in which a pair-of spaced discharge outlets extend from said trough, a single central plenum chamber is positioned in the trough between the discharge outlets, an end plenum chamber is positioned in the trough between each discharge outlet and theadjacent end of the trough, agas-permeable mediumforms the upper wall of each of the plenum chambers in the trough,

means are provided for introducing gas into each plenum chamber in the trough to pass upwardly through its gasi I permeable upper wall into overlying pulverulent material, the upper gas-permeable wall of said central plenum chamber slopes downwardly from an intermediate line towards the respective discharge outlets, and the upper walls of said end plenum chambers slope inwardly and downwardly towards their. respective adjacent discharge outlets,

11. A selfunloading bin for pulverulent material comprising side and bottom walls, said bin having an outlet opening adjacent the bottom thereof, the gas-permeable deck forming at least a portion of the bottom of the bin and inclined downwardly towards said outlet, a plenum chamber beneath said gas-permeable deck into which a gas may be introduced to pass upwardly through said deck into overlying pulverulent material to fluidize such material, a rigid support at opposite sides of the gaspermeahle deck, opposite edge portions of the gaspermeable deck extending over said rigid supports, and means for clamping opposite edge portions of the gaspermeable deck to said rigid supports, each of said clamping means including a clamping member overlying an edge portion of the gas-permeable deck and having downwardly-extending spaced portions engaging the edge portions of the gas-permeable deck only along spaced lines, fattening means for securing the clamping member in clamping position against the upper surface of the edge portion of the gas-permeable deck overlying the rigid support, said fastening means including a member passing through the edge portion of the gas-permeable deck and the underlying rigid support, a slope sheet attached to each clamping member and extending upwardly and outwardly from adjacent the inner edge of the clamping member to the adjacent side wall of the bin.

12. A self-unloading bin as set forth in claim 11 in which a portion of the upper surface of said rigid supports are raised above other portions of such surfaces to form bearing surfaces for the respective edge portions of the gas-permeable deck, and the spaced portions of the clamping member engage the upper surface of the edge portions of the gas-permeable deck along lines outwardly from the opposite edges of the raised portions of the rigid supports.

References Cited in the file of this patent UNITED STATES PATENTS 2,545,766 Cline Mar. 20, 1951 2,675,274 Engelhart Apr. 13, 1954 FOREIGN PATENTS 734,036 Great Britain July 20, 1955 

